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Tabular display of interface MTUs

When I started exploring the details of MTU handling in Cisco IOS, I quickly got tired of analyzing various long printouts to extract the MTU sizes, so I wrote a Tcl script that display hardware, IP and MPLS MTUs in a tabular format. To install it on your router:
  1. Download it from my web site and copy it to your router's flash or NVRAM.
  2. Define an alias, for example alias exec mtu tclsh flash:displayMTU.tcl.

The script recognizes two parameters: the ip parameter displays only the interfaces that have IP configured and the mpls parameter displays only the MPLS-enabled interfaces.

Here is a sample printout from one of my lab routers:
R2#mtu
Interface Hardware IP MPLS
=========================================================
FastEthernet0/0 1500 1600
FastEthernet0/1 1500
Serial1/0 1500 1500
Serial1/1 1380 1380 1430
Serial1/2 1500 1500
Serial1/3 1500
Loopback0 1514 1514
Tunnel0 1514 1476 1476

R2#mtu mpls
Interface Hardware IP MPLS
=========================================================
FastEthernet0/0 1500 1600
Serial1/1 1380 1380 1430
Tunnel0 1514 1476 1476

2 comments:

  1. Very nice script...I installed it on a few of my routers and works flawlessly...once again it demostrates the power of scripting.
  2. Ivan:

    Can you recommend a good site for TCL training/resources?

    I am a dummy as far as TCL goes, but would like to learn about it.
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